ABSTRACT: Lysophosphatidic acid (LPA) acts through high-affinity G protein-coupled receptors to mediate a plethora of physiological and pathological activities associated with tumorigenesis. LPA receptors and autotaxin (ATX/LysoPLD), the primary enzyme producing LPA, are aberrantly expressed in multiple cancer lineages. However, the role of ATX and LPA receptors in the initiation and progression of breast cancer has not been evaluated. We demonstrate that expression of ATX or each edg family LPA receptor in mammary epithelium of transgenic mice is sufficient to induce a high frequency of late-onset, estrogen receptor (ER)-positive, invasive, and metastatic mammary cancer. Thus, ATX and LPA receptors can contribute to the initiation and progression of breast cancer. Overall design: referenceXsample

Lysophosphatidic acid (LPA) acts through high-affinity G protein-coupled receptors to mediate a plethora of physiological and pathological activities associated with tumorigenesis. LPA receptors and autotaxin (ATX/LysoPLD), the primary enzyme producing LPA, are aberrantly expressed in multiple cancer lineages. However, the role of ATX and LPA receptors in the initiation and progression of breast cancer has not been evaluated. We demonstrate that expression of ATX or each edg family LPA receptor ...[more]

Project description:Autotaxin (ATX, Enpp2) is a secreted lysophospholipase D catalyzing the production of lysophosphatidic acid (LPA), a pleiotropic growth factor-like phospholipid. Upregulated ATX expression has been detected in various chronic inflammatory disorders and different types of cancer; among them increased ATX mRNA or immunohistochemical staining has been suggested in Hepatocellular carcinoma (HCC) patients. Conditional deletion of ATX/Enpp2 specifically from hepatocytes, in AlbEnpp2-/- mice, attenuated the DEN/CCl4-mediated HCC development in mice. To obtain mechanistic insights into the mode of action of the ATX/LPA axis in HCC development, we performed whole liver, genome wide expression profiling of DEN/CCl4-induced HCC upon the genetic deletion of Autotaxin (ATX) in AlbEnpp2-/- mice in comparison with DEN/CCl4-treated and untreated wt littermate mice.

Project description:LPA is a natural bioactive lipid with growth factor-like functions due to activation of series of six G protein-coupled receptors (LPA1-6). In this study we determine the LPA induced early-gene expression profile in three unrelated human cancer cell lines (MDA-MB-231, MCF7, PC3) with an objective to identify potential biomarker/s specifically upregulated through the activation of LPA receptor type 1 (LPA1) MDA-MB-231, MCF7, PC3 cells were serum starved for 24h and then stimulated with LPA (1µM) for 45min. The controls were the serum starved unstimulated cells. Two replicates for each sample were included in this study. Microarray analysis was performed using a high-density oligonucleotide array (GeneChip Human Genome U133 plus 2.0 array, Affymetrix)

Project description:Autotaxin (ATX) has been reported to act as a motility and growth factor in a variety of cancer cells. The ATX protein acts as a secreted lysophospholipase D (lysoPLD) by converting lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA), which signals via G-protein coupled receptors and has important functions in cell migration and proliferation. The current study demonstrates that ATX expression is upregulated and functionally active in FLT3-ITD+ human blasts. ATX expression was also found in normal human CD34+ progenitor cells and selected myeloid and lymphoid subpopulations. Stable transduction of mutant FLT3-ITD increased ATX mRNA in selected cell lines, whereas inhibition of FLT3-ITD signaling by sublethal doses of PKC412 led to a significant down-regulation of ATX. Moreover, results indicate that the Jun N-terminal kinase (JNK) is an important mediator between FLT3 signaling and ATX. In the presence of LPC, ATX expression led to a significant increase of proliferation. LPA caused proliferation of all tested cell lines, regardless of ATX expression and induced chemotaxis in human leukemic cell lines and human CD34+ progenitors. LPC increased chemotaxis, in cells with high expression of endogenous and exogenous ATX, by at least 80% demonstrating the autocrine effect of ATX expression. Inhibition of ATX using a small molecule inhibitor induced selective killing of ATX-expressing cell lines and reduced the motile phenotype observed in this cells. Our data suggest that the production of bioactive LPA through ATX is involved in controlling proliferation and migration during hematopoiesis and that deregulation contributes to the pathogenesis of AML. AML Classes: Molecular/cytogenetic group of acute myeloid leukemia, either internal tandem duplication (FLT3) or FLT3 point mutation (D835) or normal karyotype (NK) or t(8;21) transclocation (t821) or monosomy 7 (mono7) or inversion on chromosome 16 (inv16) or high leukocyte count normal karyotype (HL). FAB (French-American-British) Classification system for acute myeloid leukemia is provided for each sample.

Project description:Lysophosphatidic acid receptor 1 (LPA1) is a phospholipid which has been linked to adult hippocampal neurogenesis and learning deficits. Here we investigated whether LPA acts directly on the hippocampal stem cells and whether LPA1 could be a functional marker for their prospective isolation. Our results reveal that exogenous LPA increases precursor potential in vitro and net neurogenesis in vivo, an effect that is mediated by Akt activation. Using a mouse reporter line, immunohistochemistry and flow cytometry followed by in vitro cell culture, we show that, in contrast to the subventricular zone, neural precursor cells in the adult mouse dentate gyrus express LPA1-GFP. Fluorescence-activated cell sorting for LPA1-GFP in combination with Prominin-1 and epidermal growth factor receptor expression allowed the efficient isolation of a very pure population of hippocampal stem cells. Transcriptional analysis revealed a profile suggesting immune response and cytokine signaling as molecular regulators of adult hippocampal neural stem cells. Overall design: RNA from cells sorted (FACS) from the dentate gyrus of adult LPA1-GFP (lysophosphatidic acid receptor) reporter mice. Sorting was based on the markers EGFR (Egfr), LPA1 (Lpar1) and Prominin1 (Prom1). From each of 4 replicates, 3 populations (stem cells, progenitor cells, niche cells) were sequenced.

Project description:We screened highly expressed G-protein coupled receptors (GPCRs) in normal human epidermal keratinocytes (NHEKs). We then tested the effect of ligands of selected GPCRs for their potency to induce the expression of FLG, a crucial skin barrier marker gene, in NHEKs. We used CP-609,550, a JAK inhibitor, as a positive control. As a result, we identified Oleoyl-L-α-lysophosphatidic acid (LPA) as a strong FLG inducer in NHEKs. In addition, we found that LPA induced NHEKs morphological changes characteristics of differentiated keratinocytes. Notably, although CP-609,550 also induced FLG expression in NHEKs, it didn't affect NHEKs cell morphology. We further conducted comprehensive and comparative microarray analysis of gene expression induced by LPA and CP-609,550 in NHEKs. We found that LPA treatment not only induced FLG expression but also expression of several genes related to keratinocytes differentiation, epidermis development and cornified envelope. This was not observed in the CP-609,550-treated cells. Overall design: Gene expression induced by 10μM Oleoyl-L-α-lysophosphatidic acid or 1μM CP-609,550 in NHEKs were measured at 72h and compared to gene expression in the vehicle control-treated NHEKs. Three independent experiments were performed for each condition.

Project description:LPA is a natural bioactive lipid with growth factor-like functions due to activation of series of six G protein-coupled receptors (LPA1-6). In this study we determine the LPA induced early-miRNA expression profile in human breast cancer cell lines MDA-MB-231 MDA-MB-231 cells were serum starved for 24h and then stimulated with LPA (1µM) for 45min. The controls were the serum starved unstimulated cells. Three replicates were included in this study.